Designing a therapeutic hepatitis B vaccine to circumvent immune tolerance

An effective prophylactic hepatitis B virus (HBV) vaccine has long been available but is ineffective for chronic infection. The primary cause of chronic hepatitis B (CHB) and greatest impediment for a therapeutic vaccine is the direct and indirect effects of immune tolerance to HBV antigens. The resulting defective CD4+/CD8+ T cell response, poor cytokine production, insufficient neutralizing anti-body (nAb) and poor response to HBsAg vaccination characterize CHB infection. The objective of this study was to develop virus-like-particles (VLPs) that elicit nAb to prevent viral spread and prime CD4+/CD8+ T cells to eradicate intracellular HBV. Eight neutralizing B cell epitopes from the envelope PreS1 region were consolidated onto a species-variant of the HBV core protein, the woodchuck hepatitis core antigen (WHcAg). PreS1-specific B cell epitopes were chosen because of preferential expression on HBV virions. Because WHcAg and HBcAg are not crossreactive at the B cell level and only partially cross-reactive at the CD4+/CD8+ T cell level, CD4+ T cells specific for WHcAg-unique T cell sites can provide cognate T-B cell help for anti-PreS1 Ab production that is not curtailed by immune tolerance. Immunization of immune tolerant HBV transgenic (Tg) mice with PreS1-WHc VLPs elicited levels of high titer anti-PreS1 nAbs equivalent to wildtype mice. Passive transfer of PreS1 nAbs into human-liver chimeric mice prevented acute infection and cleared serum HBV from mice previously infected with HBV in a model of CHB. At the T cell level, PreS1-WHc VLPs and hybrid WHcAg/HBcAg DNA immunogens elicited HBcAg-specific CD4+ Th and CD8+ CTL responses

Praziquantel Facilitates IFN-γ-Producing CD8+ T Cells (Tc1) and IL-17-Producing CD8+ T Cells (Tc17) Responses to DNA Vaccination in Mice

BACKGROUND: CD8(+) cytotoxic T lymphocytes (CTLs) are crucial for eliminating hepatitis B virus (HBV) infected cells. DNA vaccination, a novel therapeutic strategy for chronic virus infection, has been shown to induce CTL responses. However, accumulated data have shown that CTLs could not be effectively induced by HBV DNA vaccination. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that praziquantel (PZQ), an anti-schistoma drug, could act as an adjuvant to overcome the lack of potent CTL responses by HBV DNA vaccination in mice. PZQ in combination with HBV DNA vaccination augmented the induction of CD8(+) T cell-dependent and HBV-specific delayed hypersensitivity responses (DTH) in C57BL/6 mice. Furthermore, the induced CD8(+) T cells consisted of both Tc1 and Tc17 subtypes. By using IFN-γ knockout (KO) mice and IL-17 KO mice, both cytokines were found to be involved in the DTH. The relevance of these findings to HBV immunization was established in HBsAg transgenic mice, in which PZQ also augmented the induction of HBV-specific Tc1 and Tc17 cells and resulted in reduction of HBsAg positive hepatocytes. Adoptive transfer experiments further showed that PZQ-primed CD8(+) T cells from wild type mice, but not the counterpart from IFN-γ KO or IL-17 KO mice, resulted in elimination of HBsAg positive hepatocytes. CONCLUSIONS/SIGNIFICANCE: Our results suggest that PZQ is an effective adjuvant to facilitate Tc1 and Tc17 responses to HBV DNA vaccination, inducing broad CD8(+) T cell-based immunotherapy that breaks tolerance to HBsAg

Maximum a posteriori estimation of wavefront slopes using a Shack-Hartmann wavefront sensor

Current methods for estimating the wavefront slope at the pupil of a telescope using a Shack-Hartmann wavefront sensor (SH--WFS) are based on a simple centroid calculation of the irradiance distributions (spots) recorded in each subaperture. The centroid calculation does not utilize knowledge concerning the correlation properties of the slopes over the subapertures or the amount of light collected by the SH--WFS. This paper presents the derivation of a maximum a posteriori (MAP) estimation of the irradiance centroids by incorporating statistical knowledge of the wavefront tilts. Information concerning the light level in each subaperture and the relative spot size is also employed by the estimator. The MAP centroid estimator is found to be unbiased and the mean squared error performance is upper bounded by that exhibited by the classical centroid technique. This error performance is demonstrated using Kolmogorov wavefront slope statistics for various light levels. 1 Introduction Atmosph..

Are HLA class II and immunoglobulin constant region genes involved in the pathogenesis of mixed cryoglobulinemia type II after hepatitis C virus infection?

11nonenoneAmoroso A; Berrino M; Canale L; Cornaglia M; Guarrera S; Mazzola G; Savoldi S; Scolari F; Sällberg M; Clementi M; Gabrielli A.Amoroso, A; Berrino, M; Canale, L; Cornaglia, M; Guarrera, S; Mazzola, Giuseppe; Savoldi, S; Scolari, Francesco; Sällberg, M; Clementi, M; Gabrielli, A

Differential humoral immune response against hepatitis C virus antigenic synthetic peptides in infected patients with and without mixed cryoglobulinaemia

In this study we have evaluated the prevalence of antibodies against core region peptides (residues 1–28, 21–38 and 51–68), the envelope 1, the non-structural (NS) 4 and 5 proteins of hepatitis C virus (HCV) in sera from 65 chronically HCV-infected patients, 47 with mixed cryoglobulinaemia (MC+) and 18 without (MC−). The major binding sites were located within the core region. Regions 1–28 and 51–68 were recognized by a similar proportion of MC+ and MC− patients, while peptide 21–38 was less frequently detected by samples from MC+ patients (65.5% versus 100%; P = 0.011). The patterns of the reactions showed a minimum of three binding sites: one, located within region 51–68, was shared by both groups; a second determinant was identified at residues 1–21 for MC+ patients and at residues 28–38 for MC− patients; a third, not exactly localized, lay between residues 1 and 38. Recognition of NS5 peptides was not significantly different between MC+ and MC− patients, but while the former mostly reacted either with peptide 1 (residues 2294–2309) (five of 15 sera) or with peptide 2 (residues 2304–2319) (nine of 15 sera), the latter group showed a more scattered reaction. Antibodies to HCV peptides prevalently belonged to IgG1 subclass. However, whereas IgG1 antibodies against peptide 21–38 and peptide 1 of NS5 were more frequently found in MC− rather than in MC+ patients (100% versus 63.8%, P = 0.003, and 22.2% versus 4.2%, P = 0.025, respectively), IgG3 antibodies against region 1–28 were more frequent in MC+ patients (53.19% versus 16.6%, P = 0.0078). Overall, the data suggest that a differential humoral immune response to HCV antigens occurs in patients with and without cryoglobulinaemia